Beyond the slurry: architecting binder-free tin anodes for high-energy lithium-ion batteries—a review

Abstract

Binder-free Sn anodes mitigate slurry-cast penalties—inactive mass from binders/additives/current collectors, weak interfaces, and transport resistance—by integrating Sn with a conductive substrate or scaffold. This architecture enhances adhesion, improves charge pathways, and accommodates alloying-driven volume change. Sn is attractive for high-energy-density LIBs, offering high theoretical capacity (∼993 mA h g⁻¹ for Li_4.4Sn), moderate lithiation potential (∼0.6 V vs. Li/Li⁺), abundance, low cost, and intrinsic conductivity. This Review summarizes progress in binder-free Sn anodes and distills design rules for practical cells. We first describe failure modes of binder-mediated Sn electrodes and opportunities enabled by removing polymeric components. We then classify binder-free systems by architecture–substrate pairing: (i) Sn on Cu, leveraging metallurgical bonding and controlled intermetallics; (ii) Sn integrated with carbonaceous scaffolds for compliance, percolated conductivity, and surface area; and (iii) self-supporting Sn foils enabled by scalable, solvent-free processing. Across these classes, we relate fabrication routes to structure descriptors—microstructure, porosity, grain size, and interfacial adhesion—and to transport, SEI evolution, and cycling stability. Finally, we benchmark electrode-level gravimetric/volumetric performance and outline quantitative design rules and scale-up challenges.